Venous back jets is a term used to describe the reflux of venous blood back towards the brain as a potential source of damage to nerves and myelin, and the subsequent formation of MS lesions. Venous reflux is also known as inversion flows.
Dr. Franz Alfons Schelling is an Austrian physician who began his research into the cause of mutliple sclerosis in 1973. It began while he was investigating “the causes and consequences of the enormous individual differences in the widths of the venous outlets in the human skull.
In 1981, while working at the Hosptial of Nervous Diseases in Salzburg, Dr. Schelling published his paper on his observations of “a striking widening of venous passageways through the skull in victims of multiple sclerosis.” That was just the beginning. He further sharpened his theory over the course of many decades. His book Multiple Sclerosis: The Image and Its Message, is a gem. It should be a primer for anyone seriously involved in multiple sclerosis research so that we are all reading from the same page.
Basically Schelling’s theory is based on reflux of venous blood back toward the brain. Reflux is also known as reverse flows or inversion flows as mentioned above. Schelling also refers to them as venous back jets. He suggests that the cause of the reflux can be do to normal cardiorespiratory waves and Valsalva maneuvers. They can also come from trauma.
The problem with this theory is that most veins have valves to prevent inversion or reverse flows. This includes the jugular veins (blood drainage route of the brain). To get around this, Schelling suggests that the problem could be due to incompetant jugular valves that fail to check the reverse flow thus allowing reflux, under the right circumstances, to reach the brain. On the other hand, the vertebral veins, which also drain the brain, have no valves. Having no valves is, in fact, essential to its special functions, especially in drainage of the brain during upright posture. But it also plays an important role in the movement of cerebrospinal fluid (CSF) through the brain and cord.
Another possible source of venous back jets, according to Schelling, is trauma. Severe trauma, especially whiplash, causes the contents of the cranial vault and spinal canal to rapidly shift. The contents include the brain and cord, blood and CSF. Whiplash causes all three to rapidly shift back and forth in the cranial vault and spinal canal. CSF pathways, likewise, lack valves. This means that both venous blood and CSF are free to move back and forth in reaction to the prevailing forces. In other words, whiplash causes a large (high amplitude) wave of blood and CSF to rapidly reflux back toward the brain. (see image)
The main drainage routes of the brain are called dural sinuses. The dural sinuses also have no valves to prevent venous reflux. The first ones to take the brunt of the force are largest ones. Schelling suggests that the characteristic location and appearence of MS lesions can be explained by venous reflux. MS lesions tend to be perivenular, meaning they show up around veins. But they show up around the largest veins and tend to become smaller and fewer in number as you move upstream to smaller and smaller veins counter current to venous blood flow. They also show up in the core of the brain and around the ventricles (periventricular).(see image)
The core of the brain and periventricular structures are drained by the inferior sagittal sinus, the great vein of Galen, the basal vein of Rosenthal and others. They all drain into the straight sinus, which drains into the transverse sinus. The transverse sinus drains into the sigmoid sinus (S-shaped) and exits the cranial vault into the internal jugular vein. A severe venous reflux could thus set up a tidal wave that could easily reach the smaller veins that drain the core and periventricular structures of the brain. This would further explain the fairly typical pattern referred to as Dawson’s Fingers.(see image below)
It is easy to see how violent venous back jets can be a source of destruction for delicate nerves located near the largest dural sinuses. Reflux can stretch and compress tissues in the brain, possibly to the breaking point. In fact, some researchers have suggested that even edema, that is swelling, can be sufficient to damage nerves due to over stretching them.
Cardiorespiratory waves as a source of venous reflux and nerve damage is a bit more of a stretch for me to accept even if the patient does have incompetant valves. Early on in my research I looked into bats, giraffes and whales because of the extreme inversion flows the brain contends with during head inversion and deep dives. My investigation led me to conclude that these mammals have developed compensatory mechanisms to deal with normal, albeit extreme, inversion flows. My book covers this topic in depth. If extreme back pressure was the cause then competition weight lifters, trumpet players, gymnasts, yoga masters and jet pilots would most likely have a higher incidence of multiple sclerosis.
Venous back jets like chronic cerebrospinal venous insufficiency (CCSVI) also fails to explain the gender, racial and geographical distribution differences in the incidence of MS. Nonetheless,venous back jets make the most sense when it comes to the likely role of trauma, especially whiplash type trauma, in the cause of MS lesions.
In contrast to venous back jets, my theory as to the destruction of nerves and myelin suggests that chronic craniocervical venous back pressure may be the problem. Furthermore, chronic craniocervical hypertension can decrease CSF pulsatility causing it to accumulate in the brain. It also proposes an explanation for the gender, racial and geographical distribution differences in the incidence of MS.